CN109207659B - Molten slag granulating device and heat recovery method - Google Patents
Molten slag granulating device and heat recovery method Download PDFInfo
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- CN109207659B CN109207659B CN201811164531.9A CN201811164531A CN109207659B CN 109207659 B CN109207659 B CN 109207659B CN 201811164531 A CN201811164531 A CN 201811164531A CN 109207659 B CN109207659 B CN 109207659B
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B3/00—General features in the manufacture of pig-iron
- C21B3/04—Recovery of by-products, e.g. slag
- C21B3/06—Treatment of liquid slag
- C21B3/08—Cooling slag
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B3/00—General features in the manufacture of pig-iron
- C21B3/04—Recovery of by-products, e.g. slag
- C21B3/06—Treatment of liquid slag
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
Abstract
The invention relates to a granulating device of molten slag and a heat recovery method, comprising a gas-powder flow generating process for mixing powder and compressed air; the generated gas powder flows to the molten slag flow and is sprayed to be changed into the molten slag granulation process of the high-temperature granulated slag; and the fine particle powder generated in the molten slag granulation process is used as the powder used in the gas-powder flow generation process and is returned to the molten slag powder return process circularly used in the gas-powder flow generation process. And granulating the molten slag flow into high-temperature molten particles by using the high-speed gas powder flow as a granulating medium, recycling fine slag particles obtained after cooling and screening the granulated slag as powder in the gas powder flow, and utilizing waste heat of high-temperature granulated air after granulating the molten slag. In the granulating heat recovery process of the melting furnace, the energy loss of the granulating medium is low, the impact kinetic energy to the molten slag is large, and on the premise of ensuring the slag granulating effect, the power consumption of an air source can be reduced, and high-grade hot air can be obtained.
Description
Technical Field
The invention relates to a granulating device and a heat recovery method for molten slag, in particular to a method for blowing and scattering the molten slag by using fine powder in an air flow, which can reduce power attenuation in the air flow jet process, reduce energy loss, reduce the granulating air flow, obtain high-grade hot air, ensure the vitreous body rate of the granulated slag to be used for producing high value-added products, and belong to the fields of molten slag recycling, waste heat recovery and environmental protection.
Background
The molten slag refers to the metallurgical slag discharged from a smelting furnace in a molten state in the production process of the metallurgical industry, and comprises blast furnace slag and steel slag generated in an iron making furnace, non-ferrous slag such as copper slag, lead slag, zinc slag and nickel slag generated in non-ferrous metal smelting, red mud discharged from alumina extraction from bauxite, a small amount of iron oxide slag generated in a steel rolling process and the like. The slag discharging temperature of the molten slag is about 1500 ℃ generally, the waste heat can be recovered, and the granulated slag with 90 percent of vitreous body rate can be recycled after temperature reduction. Currently, the granulated heat recovery of molten slag is mainly divided into a dry process and a wet process, but both processes are difficult to meet the needs of the current industrial development.
The wet process is a method for rapidly cooling molten slag in water under the action of thermal stress, conveying the molten slag to a slag settling tank to form water slag, and then recovering the water slag. The water quenching process before the furnace is the most common wet process in the steel industry, but has the problems of large consumption of new water, large sewage treatment capacity, low waste heat utilization, large drying energy consumption, poor equipment operation guarantee rate, generation of polluted gas and the like in the slag flushing process.
The dry process is a novel slag treatment process for carrying out molten slag granulation and sensible heat recovery by utilizing direct or indirect contact of a heat transfer medium and the molten slag under the condition of not consuming new water. Compared with wet granulation, the dry granulation process shortens the process operation, saves water consumption, does not need slag drying, has high waste heat recovery rate, reduces environmental pollution, conforms to the requirements of energy conservation and emission reduction in the ferrous metallurgy industry, and has wide technical requirements and market space. However, due to the inherent characteristics of high viscosity of the molten slag, large internal heat transfer resistance and the like, the conventional dry process generally has the problems of large power consumption of equipment, poor quality stability of granulated slag and the like, and the conventional dry process cannot be popularized in the actual industrial production in a large scale.
The air quenching method is mainly represented by a dry process technology, and is characterized in that a high-power granulation fan is used for generating high-pressure high-speed airflow to blow away and granulate molten slag flow. Because the density of the air is small, the impact force is small, and the air volume and the air pressure required by the granulated molten slag are large, the problems of large power consumption of an air source, low temperature of recovered heat exchange air and the like are caused, and the energy-saving economy is difficult to meet.
If the composition of the granulated medium can be changed and the density of the granulated medium can be increased, the granulation impact force of the granulated medium on the molten slag can be improved. And the cooled granulated slag particles are used as a granulating medium, and the granulating medium and the granulated medium have the same substance type, so that the granulated slag particles can be directly used without subsequent separation. The invention aims to develop an effective granulating device and a heat recovery method for molten slag, which can realize high-grade recovery of waste heat of the molten slag by changing a granulating medium, blowing and granulating the molten slag by taking fine-particle slag powder obtained by screening cooled granulated slag as powder used in a gas-powder flow generation process, and realizing a simpler and low-cost granulating method on the premise of ensuring that the molten slag is rapidly granulated to form a glass body and not influencing the utilization of subsequent granulated slag.
Disclosure of Invention
The invention aims to develop a device and a method for granulating molten slag, which are used for granulating the molten slag into high-temperature molten particles by using a high-speed gas powder flow as a granulating medium, recycling fine slag particles obtained after cooling and sieving the granulated slag as powder in the gas powder flow, and utilizing waste heat of high-temperature granulated air after granulating the molten slag. In the granulating heat recovery process of the melting furnace, the energy loss of the granulating medium is low, the impact kinetic energy to the molten slag is large, and on the premise of ensuring the slag granulating effect, the power consumption of an air source can be reduced, and high-grade hot air can be obtained.
The technology of the invention is realized by adopting the following scheme:
a method for granulating and recovering heat of molten slag is characterized by at least comprising the following steps:
(1) a gas-powder flow generation process for mixing powder with compressed air;
(2) the generated gas powder flows to the molten slag flow and is sprayed to be changed into the molten slag granulation process of the high-temperature granulated slag;
(3) and the fine particle powder generated in the molten slag granulation process is used as the powder used in the gas-powder flow generation process and is returned to the molten slag powder return process circularly used in the gas-powder flow generation process.
The method for recovering heat of granulating molten slag is characterized in that in the generation process of the gas-powder flow in the step (1), powder is fed by a spiral conveyor and mixed with the gas flow, or falls into the gas flow by virtue of gravity, or is sucked into the gas flow by compressed air.
The method for recycling the heat of the molten slag granulation is characterized in that the molten slag powder returning process in the step (3) comprises one of the following forms:
sieving granulated slag after further cooling after granulating the molten slag to obtain sieved granulated slag powder, and directly returning the sieved granulated slag powder to the gas-powder flow generation process for use;
or the screened granulated slag powder obtained by screening is indirectly cooled by water and then returned to the gas powder flow generation process for use;
or the screened granulated slag powder obtained by screening is returned to the gas powder flow generation process for use after being crushed and indirectly cooled by water or without being indirectly cooled by water;
or screening the screened granulated slag powder obtained by screening and dust-removing powder which is carried out by airflow and is recovered in the process of granulating the molten slag to obtain mixed powder of the screened dust-removing slag powder, and returning the mixed powder to the airflow generation process for use;
or screening the dust-removing powder which is carried out by the airflow and is recovered in the molten slag granulation process to obtain screened dust-removing slag powder, and returning the screened dust-removing slag powder to the airflow generation process for use.
The method for recovering heat from granulating molten slag is characterized in that the mass ratio of the powder in the step (1) to the compressed air is 70: 1-110: 1, the particle size of the powder is 0.2-1.5 mm.
The method for recycling the heat of the molten slag granulation is characterized in that in the molten slag granulation process in the step (2), the distance between the powder airflow jet point and the molten slag flow is 3-10 cm, and the thickness of the molten slag flow is 30-70 mm.
The method for recycling the heat of the molten slag granulation is characterized in that in the molten slag granulation process in the step (2), an included angle formed between the gas powder flow at the spraying position and the horizontal plane is 20-45 degrees.
The method for recovering heat from granulating molten slag is characterized in that in the process of granulating molten slag in the step (2), when gas powder flows to the molten slag flow for injection, the concentration of powder in the upper fluid in the gas powder flow is higher than that in the lower fluid.
The device for realizing the granulating waste heat recovery method of the molten slag at least comprises a slag launder, a gas-powder mixer, slag granulating equipment, granular slag heat exchange equipment, a dust remover and a cold ore screen; the outlet of the slag runner is connected with the molten slag inlet of the molten slag granulation equipment, the gas-powder outlet of the gas-powder mixer is connected with the gas-powder inlet of the molten slag granulation equipment, the gas outlet of the molten slag granulation equipment is connected with the gas flow inlet of the dust remover, and the granular slag outlet of the molten slag granulation equipment is connected with the granular slag inlet of the granular slag heat exchange equipment; a granulated slag outlet of the granulated slag heat exchange equipment is connected with a granulated slag inlet of the cold ore sieve, and a screened granulated slag outlet of the cold ore sieve is connected with a gas inlet of the gas-powder mixer;
or a powder crushing device and a water indirect cooling device are arranged between the cold ore sieve and the gas powder mixer, the outlet of the sieved granulated slag of the cold ore sieve is connected with the inlet of the powder crushing device, the outlet of the powder crushing device is connected with the inlet of the water indirect cooling device, and the outlet of the water indirect cooling device is connected with the gas inlet of the gas powder mixer;
or a vibrating screen is arranged behind the dust remover, a dust removal slag outlet of the dust remover is connected with an inlet of the vibrating screen, and a screening granulated slag outlet of the cold ore screen and a screening dust removal slag outlet of the vibrating screen are mixed and then connected with a gas inlet of the gas-powder mixer; or the sieving and dedusting slag outlet of the vibrating screen is connected with the gas inlet of the gas-powder mixer.
The device for realizing the heat recovery method of the granulation of the molten slag is characterized in that a gas-powder mixer for mixing gas and powder used in the generation process of the gas-powder flow at least consists of a mixer shell, a powder inlet, a gas inlet and a gas-powder outlet; the gas-powder mixer is internally provided with a material conveying section, an accelerating section, a mixing section and an injection section in sequence, wherein an outlet of the powder material conveying section is connected with an inlet of the accelerating section, an outlet of the accelerating section is connected with an inlet of the mixing section, and an outlet of the mixing section is connected with an inlet of the injection section;
or the gas-powder mixer is internally provided with a material conveying section, an accelerating section and a spraying section in sequence, and the outlet of the powder accelerating section is connected with the inlet of the spraying section;
or the gas-powder mixer is internally provided with a material conveying section, an accelerating section, a curved flow path and an injection section in sequence, the outlet of the powder accelerating section is connected with the inlet of the curved flow path, and the outlet of the curved flow path is connected with the inlet of the injection section.
The device for the molten slag granulation heat recovery method is characterized in that a curved flow path with smooth radian and capable of enabling gas-powder flow to generate centrifugal force is arranged in front of a spraying section of a gas-powder mixer, the circle center of the radian of the curved flow path is arranged on the lower side of the flow path, and the axial included angle between the inlet and the outlet of the curved flow path is 45-90 degrees.
The concrete description is as follows:
the granulating heat recovery method of the molten slag at least comprises three processes of generating gas-powder flow, granulating the molten slag and returning powder; the generation process of the gas-powder flow takes compressed air as a working medium and powder as an injection medium, and the powder enters a gas-powder mixer and is wrapped by air flow to generate stable gas-powder flow; the granulation process of the molten slag is that the gas-powder flow accelerated by air is sprayed and then collides with the molten slag flow, and the molten slag flow is granulated into granular high-temperature slag granules by utilizing the impact force of powder and the blowing-off action of air; the powder return process refers to that the powder used by the gas powder flow is from granulated slag which is screened out after being cooled, the molten slag flow is granulated into high-temperature molten slag particles by the spraying of the gas powder flow, the low-temperature granulated slag formed after the temperature of the slag particles is reduced is recycled, and part of fine-particle slag is screened out and is returned to the granulating heat recovery process of the molten slag as the powder required by the generation of the gas powder flow for recycling.
The powder is accelerated in the generation process of the air powder flow, so that air and the powder form uniform dispersion phase in the material conveying pipeline, and the speed of the air powder flow at the outlet of the air powder flow tends to be consistent. The air must overcome the powder acceleration resistance loss generated by maintaining the velocity field balance of the mixed flow and the friction resistance loss generated by conveying the powder to the injection point, so as to generate a stable air-powder flow. As shown in fig. 1, compressed air 3 generated by a high-pressure ventilator or blower 14 is taken as a working medium and enters a gas-powder mixer from a gas inlet 39, a screw shaft 12 with blades is arranged in the gas-powder mixer, the screw shaft is driven by a motor 13 to rotate, so that powder 1 is pressed into the gas-powder mixer from a feed hopper 5 through a powder inlet 38 and is pushed forwards, the screw shaft maintains the uniformity and continuity of feeding and conveying, and the pressure loss in the gas-powder flow generation process is reduced; or as shown in fig. 2, the compressed air 3 generated by the high-pressure ventilator or blower 13 is used as the working medium, the installation height of the feed hopper 5 is far greater than that of the gas-powder mixer, the powder 1 falls into the gas-powder mixer through the vertical feed section 6 by the self gravity, and the resistance loss of powder acceleration is reduced; or as shown in fig. 3, the compressed air 3 generated by the air compressor 16 is used as a working medium, the powder is sucked by the negative pressure generated by the airflow in the air-powder mixer, the powder is entrained by the air and pushed forward, the initial kinetic energy of the compressed air is enough to overcome the pressure loss in the generation process of the air-powder flow, and the compressed air is finally ejected from the air-powder outlet 37, so that the generation process of the air-powder flow is completed.
Compressed air and fine powder generate gas powder flow through a gas powder mixer, the molten slag flow is sprayed by the gas powder flow and then is crushed into high-temperature granulated slag and high-temperature heat exchange air is generated, the high-temperature heat exchange air is dedusted by a deduster and then is subjected to waste heat recovery, the high-temperature granulated slag is sequentially cooled by a granulated slag heat exchange device and screened by a cold ore screen to obtain cooled screened granulated slag powder, and the screened granulated slag powder can be directly recycled to the gas powder flow generation process as return material; or the screened granulated slag powder is further cooled by water indirect cooling equipment and then is used as a return material, and the screened and cooled granulated slag fine powder can promote the cooling effect of granulated slag in the granulation process of molten slag and improve the waste heat recovery efficiency; or crushing and granulating the screened granulated slag powder into powder with smaller particle size, and applying the powder as a return material to the air-powder flow generation process to promote granulation of the molten slag after indirect water cooling or after indirect water cooling, wherein the powder with smaller particle size can obtain better blowing-off effect of the molten slag, and the particle size distribution of the granulated slag is more uniform; fine powder can be brought out by heat exchange air flow in the process of granulating the molten slag, the dust-removing fine powder collected by a dust collector can be used as a return material for the process of generating the gas-powder flow, but the dust-removing fine powder contains a large amount of micron-sized ultrafine particles, the powder with the undersize particle size is easy to be disturbed by air flow, the impact force on the molten slag is weak, and the granulation effect is not benefited, so that the dust-removing slag powder needs to be screened, and only the dust-removing slag powder with the proper particle size is recycled for the process of generating the gas-powder flow; the granulated slag powder screened by the cold ore screen can be mixed with the dust removal slag powder collected by a dust remover, recovered and screened, and the mixture is used as a powder source in the gas-powder flow generation process.
The solid-gas ratio refers to the ratio of the mass of powder in the gas-powder flow to the mass of air. The solid-gas ratio and the particle size of the powder not only influence the power consumption in the gas-powder flow generation process, but also influence the granulation effect of the molten slag. The pressure loss of the compressed air to the powder acceleration is reduced due to the small solid-gas ratio and the small powder particle size, the large powder airflow jet speed can be maintained, and the positive influence on the airflow-powder flow generation process is realized; the advantages of high powder density can be fully utilized by high solid-gas ratio and large powder particle size, so that the gas-powder flow has higher kinetic energy and impact force in the injection process, the molten slag flow is more effectively impacted and dispersed, and the promotion of the granulation process of the molten slag is facilitated. Therefore, the selection of the solid-gas ratio and the powder particle size needs to be considered for both the gas-powder flow generation process and the molten slag granulation process so as to maintain lower power consumption and better granulation effect. The solid-gas ratio is 70-110, and the particle size of the powder is 0.2-1.5 mm, which is a reasonable interval of the granulating heat recovery method of the molten slag.
The powder and the air powder flow generated by the compressed air have balanced speed at the air powder flow jet outlet, the jetted air and the powder are subjected to the resistance action of the external air flow in a certain distance from the jet outlet to the collision of the molten slag flow, the larger the distance between the jet outlet and the impact point is, the more the speed is reduced, and in order to avoid unnecessary loss generated by the air powder flow in the jet process and reduce the granulation effect, the distance between the jet outlet and the impact point is required to be not more than 10 cm; when the distance between the molten slag flow and the gas powder flow is too close, the back-spray danger is generated, and the distance between a spray outlet and an impact point is at least more than 3 cm.
The slag can be fully granulated when the powder and the molten liquid flow are impacted and liquid drops are directly broken down, and the thickness of the slag is required to be about 30-70 mm. When the molten slag flows thickly, the powder is subjected to continuous viscous resistance in the impact process, the powder speed attenuation is large, the powder is captured by liquid drops and cannot directly break through the molten slag, so that the surface layer of the molten slag far away from the collision point cannot obtain enough powder impact energy, and the surface tension is difficult to overcome to form granulated molten slag; when the molten slag flows through the thin slag, the kinetic energy of the gas powder flow is not fully utilized, and the waste of the gas source power is caused.
When the gas powder flow impacts the surface of the molten slag at a certain angle, the surface liquid is subjected to the double actions of radial impact and shearing, the liquid surface scrapes a wave-shaped auxiliary part, and the auxiliary part forms liquid drops under the action of surface energy. The slag granulation is more easily caused by the radial impact force brought by the gas powder flow than the tangential shearing force, and the better crushing effect can be obtained by increasing the impact angle. However, the impact angle should be matched with the structural size of the granulating equipment, so that the flight distance of the granulated slag after impact is increased as much as possible to promote air heat exchange, the high-temperature granulated slag is prevented from impacting the wall of the equipment to generate adhesion, and the impact angle between the powder airflow and the molten slag flow cannot be too large. In summary, in order to achieve better granulation and heat exchange effects of the molten slag in the granulation equipment with limited volume, the impact angle between the gas powder flow and the molten slag flow at the injection position is controlled. Because the inclination angle of the slag runner is smaller, the molten slag flow flowing out of the slag runner is nearly horizontal, and as shown in figure 1, the included angle formed between the gas powder flow at the spraying position and the horizontal plane is 20-45 degrees.
When the gas powder flows to the molten slag flow to be sprayed, the gas powder flow forms a powder concentration field with a thick upper part and a thin lower part, namely the powder concentration in the upper fluid in the gas powder flow is higher than that in the lower fluid, so that the kinetic energy of the sprayed powder is favorably maintained, and the blowing effect on the molten slag flow is strengthened.
As shown in figure 4, the device for realizing the method for recovering the waste heat of the slag granulation comprises at least a slag runner 23, a gas-powder mixer 24, a slag granulation device 25, a slag heat exchange device 26, a dust remover 36 and the like, wherein compressed air 3 is used as a working medium, fine powder 1 is used as an injection medium, the powder is accelerated by compressed air in the gas-powder mixer to finish the generation process of a gas-powder flow, the granulation process of molten slag is finished in the slag granulation device, the gas-powder flow sprayed by the gas-powder mixer collides with molten slag flowing in through the slag runner 23 at a certain spraying angle α, the molten slag flow is crushed into high-temperature molten slag particles 18, the high-temperature molten slag particles 18 are discharged from the bottom of the slag granulation device to enter the slag heat exchange device, the fine powder is carried out from the collided granulated air, cleaner granulated air is captured by the dust remover to obtain the residual heat recovery, the high-temperature molten slag particles 19 are subjected to heat exchange by the high-temperature molten slag heat exchange device to generate the cooled granulated slag particles 19 and then flow into a cold slag sieve 27 to obtain a sieved gas-powder flow, the residual heat recovery is used as a sieving screen, the cold-powder flow, the residual powder flow generated by the cold-powder mixer, the cold-powder flow sieve, the cold-powder flow generated in the cold-powder flow, the cold-powder flow generated by the cold-powder flow, the cold-powder flow generated slag granulation device, the cold-powder flow generated slag granulation device, the cold-powder flow generated by the cold-powder flow-removal device, the cold-powder flow-powder flow-.
The gas-powder flow is generated in a gas-powder mixer, as shown in fig. 1, the gas-powder mixer at least comprises a mixer shell, a powder inlet 38, a gas inlet 39 and a gas-powder outlet 37; a material conveying section 7, an accelerating section 8, a mixing section 9 and an injection section 10 are arranged in the gas-powder mixer, a fine powder 1 enters the powder material conveying section of the gas-powder mixer from a feed hopper 5 through a powder inlet under the action of the stirring of a screw shaft and the self gravity or the suction force of air, then the powder is accelerated in the accelerating section to form a gas-powder flow, the gas-powder flow mixing and conveying functions are completed in the mixing section, finally the gas-powder flow is sprayed out from a gas-powder outlet through the injection section to impact a molten slag flow, and the gas-powder flow is dispersed more uniformly and stably by the mixing section arranged in the gas-powder mixer; or in order to make the gas-powder mixer simpler and more convenient, as shown in fig. 2, the gas-powder mixer is not provided with a mixing section, the transmission distance of the gas-powder flow is shortened, and the powder accelerating section is directly connected with the spraying section; or as shown in fig. 3, a material conveying section, an accelerating section, a curved flow path and an injecting section are arranged in the gas-powder mixer, and the curved flow path 11 is used for replacing the mixing section to generate a powder concentration field with a dense upper part and a dilute lower part.
As shown in fig. 3, a curved flow path 11 having a curvature capable of generating a centrifugal force in the flow path is provided in front of the gas-powder outlet 37 of the gas-powder mixer, and the center of the curvature is located below the flow path. The gas powder flow is acted by centrifugal force when passing through the curved flow path, most of powder, especially large-particle powder is sprayed out by clinging to the outer side of the elbow, and a powder concentration field with a thick upper part and a thin lower part can be formed to increase the crushing effect on the molten slag flow. The curvature and length of the curved flow path having a curvature capable of generating a centrifugal force in the flow path may be optimized according to the specific conditions such as particle size and ratio of the powder in the actual process. Generally, the curvature in the curved flow path is not less than 45 ° to ensure the centrifugal effect of the pulverized gas flow, and the curvature in the curved flow path is not more than 90 ° to reduce the local resistance caused by the turning of the pulverized gas flow.
Drawings
FIG. 1: a mixer diagram for conveying gas powder flow by a low-pressure screw pump;
FIG. 2: a low-pressure gravity flow conveying gas-powder flow mixer diagram;
FIG. 3: a high-pressure air compressor is used for conveying a gas-powder flow mixer diagram;
FIG. 4: the screened granulated slag powder is used as a return material molten slag granulation heat recovery flow chart;
FIG. 5: screening, crushing and cooling granulated slag powder as a recycling flow chart of granulating heat of returned molten slag;
FIG. 6: mixing the screened granulated slag powder and the screened dust removal slag powder to form a return charge molten slag granulation heat recovery flow chart;
1-fine powder, 2-air, 3-compressed air, 4-gas powder flow, 5-feed hopper, 6-vertical feed pipe section, 7-delivery pipe section, 8-acceleration pipe section, 9-mixing pipe section, 10-injection pipe section, 11-curved flow path, 12-screw shaft with blades, 13-motor, 14-high pressure ventilator or blower, 15-air mixer, 16-air compressor, 17-molten slag, 18-high temperature molten slag particles, 19-cooled granulated slag particles, 20-screened granulated slag powder, 21-broken smaller granulated slag powder, 22-screened dedusting slag powder, 23-slag runner, 24-gas powder mixer, 25-slag granulation equipment, 26-slag heat exchange equipment, 27-cold slag screen, 28-powder crushing equipment, 29-water indirect cooling equipment, 30-residual granulated slag powder, 31-high temperature granulated air, 32-dedusting slag powder, 33-residual dedusting slag powder, 34-vibrating slag screen, 35-air, 35-air dust removal air flow outlet, 35-3536-air flow outlet, 39-25-air flow inlet of molten slag powder, and α -air flow inlet of molten slag powder flow.
Detailed Description
Example 1:
the embodiment is a molten slag granulating device and a heat recovery method, and comprises three processes of generating gas-powder flow, granulating molten slag and returning powder, wherein the gas-powder flow generating process is as shown in fig. 1 and is generated by a low-pressure screw pump gas-powder flow mixer, a material conveying section 7, an accelerating section 8, a mixing section 9 and an injection section 10 are arranged in the mixer, the mass ratio of powder to air is 70: 1, after the powder 1 enters a powder inlet 38 from a feed hopper 5, a screw shaft 12 with blades is driven by a motor 13 to continuously press and convey the powder from the material conveying section 7 to the accelerating section 8, compressed air 3 generated by air flow power provided by a high-pressure fan or a blower 14 enters the accelerating section 8 of the gas-powder mixer from a gas inlet 39, the gas-powder mixture completes powder acceleration in the accelerating section 8 and forms gas-powder flow, the gas-powder flow mixing and conveying functions are completed in the mixing section 9, the uniform-speed uniform gas-powder flow is sprayed out from a gas-powder outlet 37 at the tail end of the injection section 10, the molten slag granulating and returning powder flow is sprayed out from a gas-powder mixing device, after the gas-powder flow is sprayed into a high-powder exchanging and colliding device, the high-powder-granulating device, the residual heat generated by a high-powder flow generated by a high-exchanging and high-generating device, the residual heat of the high-temperature slag granules 19, the residual slag granules generated after the residual slag is sprayed into a slag-powder flow generated by a slag-generating device, the high-melting slag granulating device, the slag-melting slag granulating device, the slag-.
The gas-powder flow generated by accelerating the fine powder by utilizing the high-speed air flow has higher kinetic energy and impact force, can generate more effective impact and dispersion effects on the molten slag, is beneficial to promoting the granulation process of the molten slag, can reduce the aerodynamic consumption and save the operating cost; due to the strong impact force of the powder, the air demand in the granulation process is reduced, the heat exchange is more sufficient, and the higher waste heat recovery efficiency can be obtained; the particle size of the cooled granulated slag after being screened by a cold ore sieve can meet the requirement of fine powder return, thereby not only solving the problem of fine powder source, but also realizing the effective utilization of resources. The whole molten slag granulation device and the heat recovery method have the advantages of simple flow, convenient operation, low investment cost, good waste heat recovery rate, low power consumption and stable operation.
Example 2:
the embodiment is a molten slag granulation device and a heat recovery method, which comprises three processes of gas-powder flow generation, molten slag granulation and powder return, wherein the gas-powder flow generation process is as shown in fig. 2 and is generated by a low-pressure gravity flow gas-powder flow conveying mixer, a material conveying section 7, an accelerating section 8 and a spraying section 10 are arranged in the mixer, the mass ratio of powder to air is 90: 1, the installation height of a powder feed hopper 5 is far larger than that of a gas-powder mixer, powder 1 falls into the material conveying section 7 of the gas-powder mixer from a powder inlet 38 through a vertical feeding section 6 by virtue of the gravity of the powder 1, compressed air 3 generated by a high-pressure fan or blower 13 is taken as a working medium to enter the material conveying section 7 from a gas inlet 39 to be mixed with the powder, the gas-powder flow mixture is accelerated in the accelerating section 8 and is sprayed out from a gas-powder outlet 37 at the tail end of the spraying section 10 to generate a gas-powder flow, the molten slag granulation process is basically the same as that in embodiment 1, the gas-powder flow and the molten slag 17 are subjected to acceleration in the slag granulation equipment, the powder granulation process, the powder flow is crushed at an injection angle α of 37 degrees in the molten slag granulation equipment, the molten slag granulation equipment is crushed at a high-powder flow granulation process, the crushed slag granulation equipment, the crushed powder flow is subjected to generate heat exchange, the crushed powder flow, the crushed slag granulation equipment, the crushed powder flow is taken as 20, the crushed powder 19, the crushed powder.
And crushing the residual granulated slag powder into smaller particles by crushing equipment, and further cooling by water cooling equipment to obtain the fine powder serving as a fine powder return material applied to the generation process of the gas-powder flow. The powder injection with smaller particles can promote the granulation of the molten slag, thereby ensuring better blowing-off effect of the molten slag, ensuring more uniform particle size distribution of the granulated slag, reducing air power consumption and saving operating cost; the lower-temperature powder can promote heat exchange of the granulated slag and improve the waste heat recovery efficiency. The whole molten slag granulation device and the heat recovery method have the advantages of low investment cost, good waste heat recovery rate, low power consumption and stable operation.
Example 3:
the embodiment is a molten slag granulation device and a heat recovery method, and the device comprises three processes of gas-powder flow generation, molten slag granulation and powder return, wherein the gas-powder flow generation process is as shown in fig. 3 and is generated by a high-pressure air compressor gas-powder mixer, a material conveying section 7, a bent flow path 11 and an injection section 10 are arranged in the mixer, the radian of a bent pipeline is 60 degrees, the mass ratio of powder to air is 110: 1, compressed air 3 generated by an air compressor 16 is used as a working medium to enter the material conveying section 7 of the injection gas-powder mixer from a gas inlet 39, powder in a feed hopper 5 is sucked to the gas-powder mixer by virtue of air flow suction, the gas-powder flow mixture is accelerated in an acceleration section 8, the powder is sprayed out from an elbow by the action of centrifugal force in the bent flow path 11 to form a gas-powder concentration field with a dense upper part and a lower part, the gas-powder flow with a certain concentration difference is sprayed out from a gas-powder outlet at the tail end of the injection section 10, the molten slag granulation process is basically the same as that in embodiment 1, the gas-powder flow granulation process, the gas-powder flow and the molten slag granulation process are sprayed out from a high-powder-exchange-sieving screen, the molten slag-generating device, the molten slag granulation process is used for generating heat exchange, the heat exchange of the powder generated by a heat-removing device, the molten slag granulation process is used for obtaining the molten slag granulation process, the molten slag granulation device, the molten slag granulation process is used for obtaining the molten slag granulation process, the molten slag granulation device, the molten slag granulation process, the molten slag granulation device is used for obtaining the molten slag granulation device, the.
The granulated air can be subjected to waste heat recovery after dust removal, and the dust removal powder trapped by the dust remover has a small particle size and is used as a fine powder return material to be recycled in the slag flow granulation process, so that the energy consumption generated by crushing granulated slag can be reduced, and the reasonable utilization of resources is realized. Compared with the traditional granulation process, the method has higher kinetic energy and impact force, is beneficial to promoting the granulation of the molten slag, reducing the aerodynamic consumption, saving the operating cost, strengthening the heat exchange effect and obtaining higher waste heat recovery efficiency. The whole molten slag granulation device and the heat recovery method have the advantages of simple flow, convenient operation, low investment cost, good waste heat recovery rate, low power consumption and stable operation.
Example 4:
the process of generating the gas powder flow and granulating the molten slag in the embodiment is basically the same as that in the embodiment 2, except that the powder returning process is adopted, and the cooled granulated slag is crushed by crushing equipment and is directly used for generating the gas powder flow as the returning fine powder without being cooled by indirect cooling equipment.
Compared with the embodiment 2, the embodiment still has excellent granulating effect on the molten slag, although the heat exchange capability is slightly poor, the single phase is simple in flow and convenient to operate. Compared with the traditional granulation process, the method has higher kinetic energy and impact force, is beneficial to promoting the granulation of the molten slag, reducing the aerodynamic consumption, saving the operating cost, strengthening the heat exchange effect and obtaining higher waste heat recovery efficiency. The whole molten slag granulation device and the heat recovery method have the advantages of simple flow, convenient operation, low investment cost, good waste heat recovery rate, low power consumption and stable operation.
Example 5:
the process of generating the gas-powder flow and granulating the molten slag in this embodiment is basically the same as that in embodiment 3, except that the powder returning process is performed, the fine powder required for generating the gas-powder flow is completely provided by the sieved dust-removal slag powder, and the sieved dust-removal slag powder obtained by sieving the dust-removal fine powder carried by the gas flow in the molten slag granulating process is used as the powder returning material.
The method can be used when the dust collector collects more powder. Compared with the traditional granulation process, the method has higher kinetic energy and impact force, is beneficial to promoting the granulation of the molten slag, reducing the aerodynamic consumption, saving the operating cost, strengthening the heat exchange effect and obtaining higher waste heat recovery efficiency. The whole molten slag granulation device and the heat recovery method have the advantages of simple flow, convenient operation, low investment cost, good waste heat recovery rate, low power consumption and stable operation.
Claims (6)
1. A method for granulating and recovering heat of molten slag is characterized by at least comprising the following steps:
(1) a gas-powder flow generation process for mixing powder with compressed air;
(2) the generated gas powder flows to the molten slag flow and is sprayed to be changed into the molten slag granulation process of the high-temperature granulated slag;
(3) the fine particle powder generated in the process of granulating the molten slag is used as the powder used in the process of generating the gas-powder flow and is returned to the process of returning the molten slag powder used in the process of generating the gas-powder flow;
in the molten slag granulation process in the step (2), when the gas powder flows to the molten slag flow for injection, the powder concentration in the upper fluid in the gas powder flow is higher than the powder concentration in the lower fluid.
2. The method of claim 1, wherein in the step (1) of generating the pulverized-fuel stream, the mass ratio of the powder to the compressed air is 70: 1-110: 1.
3. the method according to claim 1, wherein in the molten slag granulation in the step (2), the distance between the jet point of the powder air stream and the molten slag stream is 3 to 10cm, and the thickness of the molten slag stream is 30 to 70 mm.
4. An apparatus for carrying out a granulated heat recovery method of molten slag according to claim 1, characterized by comprising at least a slag runner, a gas-powder mixer, a slag granulation facility, a granulated slag heat exchange facility, and a dust collector; the outlet of the slag runner is connected with the molten slag inlet of the molten slag granulation equipment, the gas-powder outlet of the gas-powder mixer is connected with the gas-powder inlet of the molten slag granulation equipment, the gas outlet of the molten slag granulation equipment is connected with the gas flow inlet of the dust remover, and the granular slag outlet of the molten slag granulation equipment is connected with the granular slag inlet of the granular slag heat exchange equipment; a grain slag outlet of the grain slag heat exchange equipment is connected with a grain slag inlet of the cold ore sieve, and a screened grain slag outlet of the cold ore sieve is connected with a powder inlet of the gas-powder mixer;
or a powder crushing device and a water indirect cooling device are arranged between the cold ore sieve and the gas powder mixer, the outlet of the sieved granulated slag of the cold ore sieve is connected with the inlet of the powder crushing device, the outlet of the powder crushing device is connected with the inlet of the water indirect cooling device, and the outlet of the water indirect cooling device is connected with the gas powder opening of the gas powder mixer;
or a vibrating screen is arranged behind the dust remover, a dust removal slag outlet of the dust remover is connected with an inlet of the vibrating screen, and a screening granulated slag outlet of the cold ore screen and a screening dust removal slag outlet of the vibrating screen are mixed and then connected with a powder inlet of the gas-powder mixer; or the sieving and dedusting slag outlet of the vibrating screen is connected with the powder inlet of the gas-powder mixer;
the gas-powder mixer at least comprises a mixer shell, a powder inlet, a gas inlet and a gas-powder outlet; the gas-powder mixer is internally provided with a material conveying section, an accelerating section, a curved flow path and an injection section in sequence, wherein the outlet of the powder accelerating section is connected with the inlet of the curved flow path, and the outlet of the curved flow path is connected with the inlet of the injection section.
5. The apparatus of claim 4, wherein a curved flow path having a smooth curvature is disposed in front of the injection section of the gas-powder mixer to generate a centrifugal force on the gas-powder flow in the flow path, the curvature of the curved flow path having a center at a lower side of the flow path and a curvature of 45 ° to 90 °.
6. The apparatus according to claim 4, wherein the distance between the powder gas stream injection point at the gas-powder outlet of the gas-powder mixer and the molten slag stream is 3 to 10cm, and the thickness of the molten slag stream is 30 to 70 mm.
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| CN113932632A (en) * | 2020-07-13 | 2022-01-14 | 江苏集萃冶金技术研究院有限公司 | Process for recycling residual heat and components of dust-containing gas rich in melting gasification components |
| CN111850191A (en) * | 2020-08-25 | 2020-10-30 | 山东盛阳工程机械有限公司 | Adjustable high-temperature liquid steel slag granulating device |
| CN111996315B (en) * | 2020-08-27 | 2022-01-28 | 中冶东方工程技术有限公司 | Waste heat recovery device for molten slag |
| CN114807463B (en) * | 2022-05-26 | 2022-09-30 | 河北用邦环保设备科技有限公司 | Slag quenching and granulating equipment |
| CN115231316B (en) * | 2022-09-22 | 2022-12-20 | 山东大学 | Fluidized powder supply system and method based on waste gas and waste residue chilling steel slag |
| US20240102118A1 (en) * | 2022-09-22 | 2024-03-28 | Shandong University | System and method for delivering fluidized powder based on flue gas carrying waste slag and instant cooling steel slag |
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| CN101665845B (en) * | 2009-09-28 | 2011-06-15 | 清华大学 | Liquid blast furnace slag granulation method and device thereof |
| CN103014201B (en) * | 2013-01-18 | 2015-05-13 | 北京科技大学 | Device and method for gas-solid ejection and granulation of molten blast furnace slags |
| CN206215059U (en) * | 2016-08-09 | 2017-06-06 | 华南理工大学 | A kind of controllable mixer for gas and powder of concentration |
| CN107287370B (en) * | 2017-06-14 | 2019-02-05 | 东北大学 | " double to quench " device and method of dry granulation recycling blast furnace slag waste heat |
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